1. Field of the Invention
The present invention relates to a method and assembly for a heat sink that is attached to an electrical device.
2. Description of Related Art
Heat sinks are commonly used to remove heat from electrical devices mounted to electronic circuit boards. Most heat sinks have a plurality of fins that provide a large surface area, so that the heat can be efficiently removed by natural or forced convection. The heat is typically generated by integrated circuits that are housed within chip carriers mounted to printed circuit boards. A heat sink is typically mounted directly to the chip carrier to minimize the conductive path between the integrated circuit and the sink.
The heat sink is attached by mounting the chip carrier onto a flat surface of the heat sink. A sheet of thermally conductive adhesive film is placed between the flat surface of the heat sink and the chip carrier. The adhesive film is then heated while the chip carrier and heat sink are pressed together, wherein the adhesive bonds the two pieces together. A uniform pressure is applied to the members by a spring loaded fixture, to ensure a uniform bonding layer and to prevent shifting during cure. Another conventional method of attachment utilizes mechanical fasteners and a thermally conductive grease. It would be desirable to have a heat sink and a method of attaching the heat sink to an electrical device, without having to use an external fixture or pressure.